Zamenhof, Esperanto, and astronomy

¡SkyCaramba! Weekly astronomy blog for the week ending December 13, 2014

How are asteroids named? Whoever discovers one can propose a name to the International Astronomical Union. The object can be named after the discoverer, after a mythological figure, after a real person, or after a thing.

Yrjö_VäisäläFinnish astronomer Yrjö Väisälä liked to name asteroids after his friends. He named some after other scientists. A few he named after places including the country of Estonia. His team of asteroid hunters at the University of Turku discovered 807 asteroids. He himself discovered 128.

Two asteroids Väisälä discovered were named 1421 Esperanto and 1462 Zamenhof. The numbers tell you that respecively they were asteroid numbers 1,421 and 1,462 to be discovered. Esperanto is a constructed language developed by Ludwig Zamenhof. Väisälä spoke Esperanto and was one of its ardent advocates.

These asteroids orbit the sun between Mars and Jupiter. 1421 Esperanto takes 5.4 years to go around once and is about three earth-sun distances from the sun. Slightly farther from the sun, 1462 Zamenhof orbits in 5.6 years.

Both of these asteroids are very dim. Reflecting light to us at only 17th magnitude, you will need a very large telescope and very dark skies to see them. Väisälä studied optics and had access to university equipment in a country with long winter nights, so he had advantages most of us don’t. Many asteroid observers don’t see such dim objects directly. Instead, they wait for an asteroid to pass in front of a brighter star and temporarily block its light. That’s called an occultation.

The next time one of these asteroids occults a star will be on November 2, 2015. For about five minutes, 1462 Zamenhof will hide from view a 12th magnitude star for people watching from the eastern United States and the northern Atlantic.

There are two asteroids named after Yrjö Väisälä. They are 1573 Väisälä and 2804 Yrjö. He didn’t discover either, but his research team in Turku discovered one.

Should you ever discover an asteroid, you can name it after yourself, someone else, a place, or a thing. But don’t expect it to be a fast process. There are about 400,000 known asteroids now. Just 16,000 have names. The International Astronomical Union would take on an extraordinary workload to name them all.

You see, even though it’s up to the discoverer to name the object, it’s not a case of anything goes. The name can’t be offensive and it can’t be too similar or identical to that of another asteroid or moon. And besides not wanting to offend or confuse anyone, the IAU doesn’t feel much pressure to give them all word names. For most astronomers, the numbers are fine by themselves.

I bring up the asteroids named Zamenhof and Esperanto at this time because December 15 is a special day for many Esperanto speakers. It’s Zamenhof’s birthday. Some regard the day as Esperanto Day.